ratatui-image

Showcase:

Image widgets with multiple graphics protocol backends for Ratatui

⚠️ THIS CRATE IS EXPERIMENTAL, AND THE TERMWIZ RATATUI BACKEND DOES NOT WORK

Render images with graphics protocols in the terminal with Ratatui.

Query the terminal for available graphics protocols (or guess from $TERM or similar).

Some terminals may implement one or more graphics protocols, such as Sixels or Kitty's graphics protocol. Query the terminal with some escape sequence. Fallback to "halfblocks" which uses some unicode half-block characters with fore- and background colors.

Query the terminal for the font-size in pixels.

If there is an actual graphics protocol available, it is necessary to know the font-size to be able to map the image pixels to character cell area. The image can be resized, fit, or cropped to an area. Query the terminal for the window and columns/rows sizes, and derive the font-size.

Render the image by the means of the guessed protocol.

Usually that means outputting some escape sequence, but the details vary wildly.

Quick start

use ratatui::{backend::{Backend, TestBackend}, Terminal, terminal::Frame};
use ratatui_image::{picker::Picker, ResizeImage, protocol::ResizeProtocol};

struct App {
    // We need to hold the render state.
    image: Box<dyn ResizeProtocol>,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let backend = TestBackend::new(80, 30);
    let mut terminal = Terminal::new(backend)?;

    // Should use Picker::from_termios(), but we can't put that here because that would break doctests!
    let mut picker = Picker::new((8, 12));
    picker.guess_protocol();

    let dyn_img = image::io::Reader::open("./assets/Ada.png")?.decode()?;
    let image = picker.new_resize_protocol(dyn_img);
    let mut app = App { image };

    // This would be your typical `loop {` in a real app:
    terminal.draw(|f| ui(f, &mut app))?;

    Ok(())
}

fn ui<B: Backend>(f: &mut Frame<B>, app: &mut App) {
    let image = ResizeImage::new(None);
    f.render_stateful_widget(image, f.size(), &mut app.image);
}

Graphics protocols in terminals

Different terminals support different graphics protocols such as sixels, kitty-graphics-protocol, or iTerm2-graphics-protocol. If no such protocol is supported, it is still possible to render images with unicode "halfblocks" that have fore- and background color.

The [picker::Picker] helper is there to do all this graphics-protocol guessing, and also to map character-cell-size to pixel size so that we can e.g. "fit" an image inside a desired columns+rows bound etc.

Widget choice

The [ResizeImage] widget adapts to its render area, is more robust against overdraw bugs and artifacts, and plays nicer with some of the graphics protocols. The resizing and encoding is blocking by default, but it is possible to offload this to another thread or async task (see examples/async.rs).

The [FixedImage] widgets does not adapt to rendering area (except not drawing at all if space is insufficient), may be a bit more bug prone (overdrawing or artifacts), and is not friendly with some of the protocols (e.g. the Kitty graphics protocol, which is stateful). Its only upside is that it is stateless (in terms of ratatui), and thus can never block the rendering thread/task.

Examples

examples/demo.rs is a fully fledged demo:

• Guessing the graphics protocol and the terminal font-size.
• Both [FixedImage] and [ResizeImage].
• [Resize::Fit] and [Resize::Crop].
• Reacts to resizes from terminal or widget layout.
• Cycle through available graphics protocols at runtime.
• Load different images.
• Cycle toggling [FixedImage], [ResizeImage], or both, to demonstrate correct state after removal.
• Works with crossterm and termion backends.

examples/async.rs shows how to offload resize and encoding to another thread, to avoid blocking the UI thread.

The lib also includes a binary that renders an image file.

Features

• sixel (default) compiles with libsixel.
• rustix (default) enables much better guessing of graphics protocols with rustix::termios::tcgetattr.
• crossterm or termion should match your ratatui backend. termwiz is available, but not working correctly with ratatu-image.
• serde for #[derive]s on [picker::ProtocolType] for convenience, because it might be useful to save it in some user configuration.

Current version: 0.4.1

Sixel compatibility and QA:

Latest Xterm testing screenshot:

Halfblocks should work in all terminals.

Comparison:

• viuer Renders graphics in different terminals/protocols, but "dumps" the image, making it difficult to work for TUI programs. The terminal protocol guessing code has been adapted to rustix, thus the author of viuer is included in the copyright notice.
• yazi Not a library but a terminal file manager that implementes many graphics protocols and lets you preview images in the filesystem.

License: MIT